Grains Research and Development

Date: 30.06.2014

Drainage takes water management to new level

Author: Rebecca Thyer

Photo of man kneeling in field

Stott Redman has replaced raised beds with intensive drainage to overcome waterlogging on his Hopetoun property.

PHOTO: Evan Collis

With an average annual rainfall of 475 millimetres, Hopetoun grower Stott Redman regularly confronts a double-edged sword. “We are lucky to be cropping in a mid-to-high-rainfall zone,” he says, but with the rain comes waterlogging and crop stress.

The issue is particularly pronounced on the farm’s shallower, sandier soils: “These soils waterlog quickly but also dry out quickly. It can be hard to manage a dry month after a wet month.”

Waterlogging and the goal to improve water use efficiency has seen the Redmans, who farm nearly 6500 hectares of highly variable soil in Western Australia’s south-east, create an intensive drainage system across 80 per cent of the property.

The drains were designed by feeding real-time kinematic data – showing elevation and topography – into a software program called Grade Design. This information was then relayed to the Redmans’ tractor, which pulled a scraper, while a contracted excavator cut the more difficult drains.

Scraper-made drains are mostly found in the paddocks. At three to four metres wide, they have a flat bottom so that machinery can drive through them. They range from as shallow as 20 centimetres to as deep as one metre.

Using a laser level, an excavator cut drains that were too deep or rocky for the scraper. These drains are 1.5m wide and range from 0.5 to 3m in depth. They are V-shaped, with a flat bottom.

“The drains let the water gently run off into natural water courses without impeding our work. They keep the landscape drier, reducing our risk of waterlogging.”

Stott says the process has taken about three years and will require some ongoing maintenance but has been worth it. “We have noticed the difference already. Where we would have seen waterlogging, stressed plants and a below-average season, we can achieve an average season.”

Stott bought the former sheep property 10 years ago and had tried raised beds as a way to manage waterlogging. After a few years, he decided it was time to try something else: “I felt they were slowing us down. Our tramlines were also full of water –  it seemed like we were always driving through water. In our system, I think we can achieve more with drainage. And now we can run through the paddocks unimpeded, which wasn’t the case before.”

Other on-farm improvements include the use of cover crops, mainly millet, for better soil health. “The benefits of cover crops have been proven across the world and we want to make them work for us.”

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Omega-3 oil to come from oceans of canola

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Region West